apache/spark — pull request #3205 by haitaoyao (2014-11-11 08:35:51+00:00)
Title: add substitude for java opts, too.

add substitute args for while forking java process.
So we can set extra java opst like this:

```
-XX:+PrintGCDetails -XX:+PrintGCDateStamps -verbose:gc -Xloggc:/tmp/spark.executor.{{HOSTNAME}}.{{APP_ID}}.{{EXCUTOR_ID}}.gc.log
```
to avoid gc log to be overwriten